1. Field of the Invention
This invention relates to an article comprised of an aggregate of restrained tubular rubbery bodies useful as a vibration isolation or shock absorbing structure.
2. Background of the Prior Art
Vibrations are caused by many sources, including, for example, the operation of heavy machinery, construction operations, such as digging, pile driving, and blasting, climatic conditions such as wind, thunder and earthquakes, and by other sources. The transmission of such vibrations through various rigid structures to other rigid structures creates numerous problems, such as premature wear, damage or destruction of equipment, occupational injury in some instances, interference with sensitive equipment used in the same vicinity, and other problems. In some instances, a brief, unexpected vibration can destroy or severly damage a fragile instrument, structure or work of art such as an intricate porcelain figurine. Vibration problems are particularly acute in areas for example where sensitive scientific equipment such as infrared spectophotometers, X-ray analysis equipment and the like are used in the same building or the same vicinity as heavy equipment such as a mineral crusher, mixer, punch press, or grinder. The vibration of such equipment can cause undesirable background noise in such instruments to such a degree as to interfere with or completely eliminate any accuracy which the instrument was engineered to exhibit.
Numerous attempts have been made to eliminate transmission of vibrations by either isolating the more sensitive piece of equipment, the vibration-inducing piece of equipment, or both, by means of devices designed to prevent the transmission or dampen or absorb unwanted vibrations. Such devices, known in many embodiments, are generally resilient or have a resilient element which may be interposed between structures to reduce or eliminate the transmission of vibrations therebetween. For example, springs have been used as vibration isolation elements with some success, but they do not generally perform completely satisfactorily. Other vibration isolation articles are known. For example, it is known to utilize segments of solid rubber of open- or closed-cell rubber foams as vibration isolation structures. The solid rubber isolators do not generally completely eliminate all transmission of vibrations. Foams, at the porosity necessary to provide satisfactory isolation, are subject to structural failure in a relatively short period of use. Resilient air bags which may be self-contained or connected to a continuous source of compressed air have also been employed as vibration isolation elements. Prior to the present invention, air bags have been the most efficient vibration-isolating elements, but these also fail after relatively short periods of use particularly under overload, and in a use environment which could perforate the bags.